Formula, Valency and Equation

Chemistry Board Question
Chapter Four

Formula, Valency and Equation
Short Questions
1. What do you mean by structural formula? Write down the structural formulae of acetylene and Ammonia. (DB-04, 05, SB-03, CB-99) 1+1=2
2. i) What is meant by a structural formula and how it can be expressed. Write down the structural formulae of Pentane, Hydrazoic acid and C2H4. (JB-04, BB-04, RB-03, CB-02, JB-00, RB-05), Sulphuric acid (CB-02), Tetra bromo ethane (CtgB-01, 1,1 di iodo ethane (CtgB-01, Glycerine (CtgB-01), Hydrogen Cyanide (SB-04), Ammonia (SB-02), Acetylene (SB-02), Nitric acid (RB-05), HCl (SB-04, N3H (SB-04), 
 ii) What is heavy water? (JB-01) 1
3. What is valence electron? (DB-02) 2
4. What do you mean by variable valency? Write with example. (RB-02, SB-02, DB-99) 2
5. Write down the four differences between empirical and molecular formula. (BB-05, SB-04, DB-05, BB, CB-03, RB-05, CB-05) test 08 2
6. Write the rules for writing symbols. (BB-05) 2
7. What is dormant valency? (BB-04, RB-4, DB-05) 1
8. Write down the differences between empirical formula and molecular formula. (CB-02, SB-02, 01, JB-99, DB-05) 2
9. Write down the rules for writing molecular formula of compounds. (DB-03) 2
10. i) Write the method for determining the molecular formula. (DB-03) 2
 ii) Write down the rules for the determination of molecular formula from the empirical formula. (SB-01, DB-02, RB-02)
11. Write down the name and formula of a monovalent positive compound radical. (CB-01) 1
12. Define active and dormant valency. Write with example. (JB-03) 2
13. Find out the active and dormant valency of the following compounds. 2
 (i) PCl3 (Phosphorous trichloride (ii) SO3 (Sulphur trioxide) (SB-02, CtgB-03, DB-05) 2
14. Write down the empirical and molecular formula of Benzene and glucose. (SB-04) 2
15. Write down the significance of H2SO4, HNO3 and H2O. (DB-03, DB-99, RB-04) 13=3
16. Write the two significance of HNO3. (SB-04) 1
17. Write down the difference between valency and ions. (SB-01) 2
18. A compound contains 32.38% sodium, 22.57% sulphur and 45.05% oxygen. Find out its empirical formula. (CtgB-02) 2
19. i) Write the rules for determination of empirical formula from percentage composition. (CtgB-05) 2
 ii) Write, how empirical formula can be determined from percentage composition of a compound. (SB-02) 2
20. i) Write the three quantitative significance of the reaction, C+O2=CO2. (CtgB-02) 2
 ii) Write down the significance for the chemical equation. (DB-01, CB-01) 2
  a) N2+3H2 = 2NH3 (BB-05)
  b) H2+Cl2 = 2HCl (DB-01, CB-01)
  c) Zn+H2SO4 = ZnSO4+H2 (SB-03, DB-03)
21. Find out the percentage composition of (i) H2O (ii) Perchloric acid. (BB-01, DB-99, BB-04, DB-05) (iii) Glucose. (JB-5) 2
22. Write the formula of Ozone gas. (JB-2) 1
23. i) What is meant by radicals? (SB-01, BB-05) 1
 ii) What are the differences between compounds and compound radicals. (CtgB-04) 2
24. Write down the formula of di-basic acid? What is di acidic base? (CtgB-04) 1
25. What is empirical formula? (SB-01) 2
26. What is radical? Write the symbol and valency of three radicals. (BB-01) 2
27. Write the symbol and valency of five radicals. (SB-02) 2
28. What is called composition? (JB-05) 1

Broad Questions
29. i) What is a chemical equation? Write down the significance for the chemical equation N2 + 3H2 2NH3 (SB-05, BB-05) 3
 ii) Significance : 2H2+O2 = 2H2O (DB-02, 01, CB-01) 2
30. What do you mean by maximum, active and dormant valency. (BB-02, CB-01, SB-99) 3
31. A compound contains 85.71% carbon, 14.29% Hydrogen and its vapour density is 28. Find out its Molecular formula. (RB-02, CB-99, CtgB-01, SB-01) 3
32. What is molecular formula? The empirical formula of glucose is CH2O. Its molecular mass is 180. Find out the molecular formula of glucose. (JB-99) 3
33. A compound contains C=92.3% and Hydrogen=7.7%. Its molecular mass=78. Find out its molecular formula. (JB-01) 3
34. A compound contains 32.4% Sodium, 22.5% Sulphur and 45.1% Oxygen. Find out its simple emperical formula. (DB-02, JB-04) / A compound having (Na=32.4%, S=22.5% and the rest is O2. Calculate its empirical formula) 3
35. A compound contains C=26.72%, H=2.24% and O=71.04%. Its vapour density is 45. Find out the molecular formula of the compound. (CB-03) 3
36. In the percentage composition of a Carbohydrate C=54.54%, H=9.09% and O2=36.36%. Vapour density of the compound is 44. What will be its molecular formula? (CtgB=01) 2
37. In the percentage composition of glucose C=40% and H=6.67%. What will be its empirical formula? (SB-03) 2
38. A compound comtains C=32%, H=4% and O2=64%. Its vapour density is 75. Find out its molecular formula. (SB-01, BB=05)pre08 4
39. A compound containing C, H and O2 where H=2.24% and C=26%. The molecular mass of the compound is 90. Find out its molecular formula. (SB=03, RB=05) 2
40. In a compound of Carbon, Hydrogen and Oxygen the percentage of C=40% and H=6.67% respectively. The molecular mass of the compound is 180. Find out its moleculr formula. What is the name of the compound? (DB-01) 4
41. A compound contains 14.3% carbon, 1.19% Hydrogrn and the rest portion is chlorine. The vapour density of the compound is 84, find out its molecular formula. (JB-05) 3